LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 515 
Three weeks after the operation the weakness of the left side was still very evident. 
There was feeble power of extension and flexion of the left thigh and extension of the 
left leg; the left foot was dragged in walking; the left arm was generally kept by the 
side in a semiflexed position, but some flexion of the forearm and flexion of the fingers 
was occasionally observed in struggling. 
A few days subsequently it was seen, when struggling to lay hold of a piece of apple 
with its right hand and not able to reach it, to put forth its left hand feebly and close 
its fingers over it. 
At this period the animal was held while the resistance to passive movements of the 
limbs respectively was tested. There was very feeble power of resistance to passive 
movements of the left leg, while this was very vigorous in the right. There was in 
the left arm special resistance to the passive extension of the forearm. 
A month after the operation the animal was able to move about actively and climb. 
In climbing the left hand was used feebly to grip the bars of the cage, but no weight 
was rested on it. The left foot was dragged in wmlking, and no grip was made with 
it in attempts at climbing. 
The left patellar reaction was greater than the right. The cremasteric reflex was 
more distinct on the right than left side. The cutaneous sensibility was to all 
appearance equally acute on both sides ; pinching, heat, &c., eliciting equal attention 
and signs of uneasiness. 
Two months after the operation the weakness of the left arm was still very evident. 
The animal could use it feebly both in climbing and for prehension. The left leg was 
especially weak. In attempts at climbing the left leg was only feebly flexed and 
never raised so high as the other, while the grip of the toes was almost nil. In 
jumping down the animal always alighted only on the right foot. 
Ten days after the last observation a lesion was established in the left hippocampal 
region, the effects of which will be described subsequently (Section 5, Experiment 
24"' r ). Continuing the history of the condition of the left side, it was found, on exami¬ 
nation eight months after the operation, that while the animal was struggling against 
being held, the left leg was little or not at all used. Vigorous gripping was made with 
the right. There was evident rigidity of the left leg. The foot was kept more or less 
pointed, and dorsal flexion caused great tension of the sural muscles. The left 
hand was very feeble as compared with the right, and there was considerable 
resistance to passive extension of the forearm,—the biceps and other flexors of the fore¬ 
arm becoming tense. 
The left patellar reaction was exaggerated. The left superficial reflexes were 
generally less distinct than the right. 
The animal resented pinching, pricking, &c., on the left side as much as on the right. 
Fifteen months after the operation the condition was similar. It was observed at 
this time that frequently when the animal was resting its weight on the left foot, 
clonus came on, causing the leg to dance. 
3 u 2 
